长江流域“2012·07”暴雨洪水分析

Analysis of Storm Flood Occurred in Yangtze River Basin in July 2012

2012年7月,长江流域先后出现4次强降雨过程,发生了4次洪水,其中朱沱江段水位超过历史实测最高记录,寸滩江段发生1981年以来最大洪水,三峡水库出现建库以来最大入库洪峰;长江上游干流宜宾至寸滩江段全线超过保证水位,中游干流石首至螺山江段及洞庭湖全线超过警戒水位。在调控"2012·07"洪水过程中,三峡水库有效降低荆江江段最高水位超过2m,洪湖江段超过1m,避免了长江荆江江段出现接近保证水位的高水位,缩短了长江中下游超警江段240km,大大减轻了中下游的防洪压力。

In July 2012, four intensive rainfall processes occurred successively in the Yangtze River Basin, leading to four floods. Among them, water level of the Zhutuo Rreach exceeded the maximum observed record; the Cuntan reach experienced the heaviest flood after 1981; the highest flood peak appeared in the Three Gorges Reservoir; water level in the reach from Yibin to Cuntan located in the upstream the Yangtze River exceeded the guaranteed stage; the water level in the reach from Shishou to Luoshan in the Dongting Lake exceeded the warning stage. During the process of flood regulation and control in July 2012, the Three Gorges Reservoir played an effective role in reducing the water levels by 2m in the Jingjiang reach and 1 m in the Honghu reach. Thus, the situation that water level in the Jingjiang reach approach to the guaranteed stage was avoided, and the length of the reach with water level exceeding the warning stage was shortened by more than 240km in the middle and lower Yangtze River, which mitigated the pressure of flood control in this area.